Asphalt composition and method of making same



drophilic to hydrophobic.

Patented Mar. 39, 1954 UNITED STATES PATENT OFFICE Frederick H.MacLaren, Munster,

to Standard Oil Company,

poration of Indiana Ind., assignor Chicago, 111., a cor- No Drawing.Application June 30, 1950, Serial No. 171,556

The present invention is directed to improvements in bitumencompositions, and particularly in mineral aggregate coatingcompositions, and

more particularly relates to bitumen compositions having improvedadherence to damp or unless the aggregate is substantially dry, and forthis reason, in conventional pavements or road construction practice itis customary to dry the mineral aggregate by suitable well knownmethods. Furthermore, water entering the road or pavement during servicemay have a detrimental effect in that it may displace the oil or bitumenfrom the surface of the aggregate and thus diminish the bonding effectof the oil and/or bitumen. This materially shortens the life of the roador pavement requiring frequent repairs and is, therefore. uneconomical.

Mineral aggregates employed in road or pavementconstruction range incharacter from hy- In general, siliceous and acidic minerals tend to behydrophilic, while calcareous alkaline minerals tend to be hydrophobic.It has been observed that the mineral aggregates appear to have agreater attraction for water than for oil or bitumens and that it isdifiicult to obtain by conventional methods complete or satisfactorycoating of aggregates by "oil or bitumen when water is present.Furthermore, even though satisfactory coating is obtained by using dryaggregate the oil or bitumen tends to be displaced if water enters thepavement or road.

It is known that the coating of damp or wet mineral aggregates by oil orbitumen may be effected, and the resistance of the coating todisplacement or stripping by water improved, by treating the aggregatewith small amounts of a water-soluble soap of a fatty acid inconjunction with a water-soluble salt of a polyvalent heavy metal oractivator. For optimum results with these reagents, the relative amountsof the two reagents must be carefully adjusted. Thus, when a divalentheavy metal is used as activator; the

-amount of soap used should be substantially one mole per mole ofactivator; with a trivalent ,metal, between one and two moles of soapper mole of activator. Use of larger amounts of soap than thisdiminishes the effect obtained and this diminution of effect increaseswith ex- .cess of soap over the proportions given until,

when the amount of soap becomes equivalent to the activator, i. e. twomoles of soap per mole of divalent metal or three per mole of trivalentmetal, the beneficial of the reagents substantially disappears. I

The above method has the disadvantage that the relative amounts of soapand polyvalent 9 Claims. (Cl. 106269) heavy metal activator are criticaland must be carefully adjusted for optimum results. Use of an excess ofsoap over the optimum amount diminishes rather than enhances the effectobtained; the use of excess heavy metal to avoid the danger of excesssoap is not harmfulbut increases the cost. Furthermore, the two reagentsmust be weighed or measured out and added to each batch, as neither issoluble in the oil or bitumen; while this disadvantage may be partiallyovercome under favorable conditions by using in place of the soap afatty acid dissolved in the oil or bitumen, this expedient is effectiveonly under favorable conditions of low moisture content of theaggregate, adequate and eificient .mixing, etc.

Under conditions which are not at all severe, such as appreciableamounts of water and/or facilities for only moderately eflicient mixing,fatty acids appear not to be sufiiciently soluble in water to reach andreact with the heavy metal ion to the required extent, and if addeddirectly to the mixture or dissolved in the oil or bitumen, arepractically without effect.

Another important disadvantage of the above method is that a heavypolyvalent metal salt must be used with the soap. Furthermore, it hasbeen found that while some limestones appear capable of adsorbing orreacting with polyvalent heavy metal ions and accordingly respond tosome degree to the above method, a great many others do not and withthese it is difiicult or impossible object of the present invention isto provide a coating composition for mineral aggregates which will notbe stripped therefrom by aqueous liquids. Still another object of theinvention is to provide a coating composition for mineral aggregatewhich can be applied without the necessity of drying the mineralaggregate and which will adhere thereto even in a wet condition. Anotherobject of the invention is to provide a method of preventing strippingof the coating composition from the mineral aggregate by water after theroad and/0r pavement is constructed. A further object of the inventionis to provide a method of promoting the adherence of oil bituminousmaterials to siliceous aggregates without thenecessity of drying thelatter. Other objects and advantages of the invention will becomeapparent as description thereof proceeds.

In accordance with the present invention bitumens such as for example,road oils and asphalts having improved properties and adherence to wetmineral aggregates are obtained by incorporating in such bitumens fromabout 0.1% to about 30%, or more by weight, and preferably from about 3%to about by weight, of the propane insoluble fraction obtained in thepropane extraction of crude fatty materials, such as animal, marine andvegetable fats, fatty oils or fatty acids split therefrom. This propaneinsoluble fraction, which is obtained as a residue, in amounts of theorder of about .2 to 2 Weight percent, in the propane fractionation ofsuch crude fatty materials contain most of the color bodies which werepresent in the crude fatty materials. Because of their very dark colorthey are referred to in commerce as ebony fats. The properties ofrepresentative samples of the propane insoluble residues obtained fromanimal fats and animal vegetable oils on a water-free basis, areapproximately as follows:

Residue f1 cm from Animal Vegetable Fat Oil Residue Property Viscosity,Seconds Saybolt at 100 F 6, 500 930 Viscosity Seconds Saybolt at 130 F1,860 430 Viscosity, Seconds Saybolt at 10 F 300 100 Ash, Weight Percent1.3 06 A. P. I. Gravity, degrees... l0 l6 Acidity ASTM (D4304), mg.KOH/gui 41 63 Pentane Insoluble, Weight Percent 2. 6 4. 2 BenzeneInsoluble, Weight Percent. .7 1.0 Saponification Number 190 170 PercentFatty Acid. 31 Iodine Number 58 106 a suitable temperature, namely fromabout 100 F. to about 200 F., incorporating the desired amount of theherein-described residue and thoroughly mixing the two materials bysuitable means until a homogeneous product is obtained. The grade ofmaterial, with respect to viscosity, determines the degree of heatingprior to mixing with the bituminous material.

The effectiveness of the herein-described propane insoluble residues inenhancing the adherence of bitumens to damp or wet mineral aggregatescan be readily determined by the following test:

Fifty grams of the mineral aggregate, which may be 20 or 30 mesh acidicaggregate, such as Ottawa sand, or calcareous aggregate, such as Bad Axelimestone, are covered with water and the excess drawn off. Two grams ofthe bitumen material to be tested are then added to the Wet aggregate ina beaker and the mixture stirred for about one minute. The coating isthen visually observed to note whether or not the aggregate isadequately coated. Following this, the beaker is half-filled with waterand the extent of stripping as evidenced by the amount of oil whichleaves the aggregate and floats to the surface of the water isestimated. A reading of 0 to 10" is given based on a compositeevaluation arrived from two observations in the test. A value of 10indicates perfect coating and no stripping. The effectiveness of thepropane insoluble residue from animal and fatty materials in improvingthe adherence of bitumens to both siliceous and calcareous mineralaggregates is demonstrated by the data in Table I which were obtained bysubjecting the following samples to the foregoing test:

Sample 1.--Residual oil +no propane insoluble residue of the type hereindescribed.

Sample 2.-Residual oil +no propane insoluble residue of the type hereindescribed.

Sample 3.-Residual oil +3% propane insoluble residue from crudevegetable fatty oils.

Sample 4.Residual oil +5% propane insoluble residue from crude animalfats.

Sample 5.Residual oil +5% propane insoluble residue from crude animalfats.

The method of fractionating the animal, marine and vegetable fattymaterials with propane is Well known to those skilled in the art and iscommonly referred to as the Solexol process currently in commercial useand described in Industrial and Engineering Chemistry, February 1949, p.280. A system for effecting such fractionation is described inconsiderable detail in U. S. 2,505,338. For most crude animal fats,marine oils and vegetable oils and similar fatty materials, includingacids split from such fats, the fractionation conditions are employedwhich give a propane insoluble residue of about 1%, i. a, about 0.2 to2%, although in some cases such residue may be as large as 5% or even10%.

Bitumens containing the herein-described propane insoluble residue ofcrude fatty materials are readily prepared by heating the bitumen toCracked residuum diluted with light aromatic stock to give a product ofthe following specifications:

Flash Not less than 150 F. Furol viscosity at 140 F -200 seconds.

Inspection of residue after distilling to 680 F.: AS'LM penetration at77 IL- 120-300. ASTM ductility at 77 F Not less than 100. ASTM ductilityat 60 F Not less than 100.

CC! solubility Not less than 99.5

about 150 F. on mixtures of asphalts and the propane-insoluble residuefrom crude fatty materials indicate good iompatibility of the additivewith bituminous materials and substantially no loss in coating powerafter long periods of storage.

Th amount of the propane-insoluble residue from fatty materials employedin admixture with bitumens depends upon several factors, among which arethe type of the bituminous material, the area of the aggregate-bitumeninterface, the characteristics of the aggregate surface, and theseverity of the conditions of use. For example, as is well known tothose skilled in the art, bitumens of different types vary in what canbe called inheren coating ability; some exhibit moderate ability to coatdamp or wet aggregates while others exhibit little or no ability to coatsuch aggregates. This appears to be a character,- istic or propertywhich cannot be predicted by analysis or from other properties.Accordingly, the amount of coating agent required for the same serviceconditions will vary with different bitumens. The area of theaggregate-bitumen interface also influences the amount of the coatingagent to be used. It will be understood by those skilled in the art thatthis area depends upon the particle size distribution, particle shapeand the degree of surface roughness and upon the properties of theaggregate and the bitumen. Furthermore, the surface characteristics ofthe aggregates vary extensively as regards the amount of the coatingagent required to give a satisfactory coating since some aggregates aremore hydrophilic than others and require a higher concentration of thecoating agent per unit area of surface. Finally, the severity of theconditions under which it is desired to coat the aggregate, particularlyas regards the amount of water upon the aggregate and the efliciency ofthe mixing facilities will affect the amount of coating agent required.Since the foregoing factors are interdependent to some extent, theamount of coating agent which can most advantageously be used should bedetermined for the individal combination of bitumen and aggregate. Asaforesaid in general, the quantity of the propane insoluble residue offatty materials required will vary from about 0.1% to about 30% or moreby weight, and preferably from about 3% to about 10%, by weight, basedupon the bitumen employed.

Another property of the herein-described propane-insoluble residues isthat of increasing or raising the flash point of bitumen, such asasphalts to which it is added. The efiect of the addition of theherein-described additives on raising the flash point of bitumens towhich they are added is illustrated by the data in Table II which wereobtained with asphalts containing 5% of a propane-insoluble residue fromcrude animal fats:

6 It will be noted from the above data that both low flash and highflash bituminous materials are improved by the addition of the hereindescribed additive.

While the present invention has been described with reference to itsapplication of the coating of mineral aggregates with bituminousmaterials with special reference to highway and/or pavement surfacing,the invention is also applicable to the preparation of other products inwhich the water resistant bond between mineral substances and bituminousmaterials is advantageous or necessary. For example, the invention canbe adapted for the preparation of bituminous grouts, mastic-s, caulking,or sealing compounds, enamels or for pipe dips; for the preparation ofimproved bituminous water-preventing agents for ma sonry; for thepreparation of filled asphalt products comprising asphalt and very finemineral fillers, such as are used in composition shingles or roofing; orfor improving the adhesion of mineral granules to asphalt-surfacedroofing, etc.

The terms bituminous materials or bitumens as used herein refer to anymixtures of hydrocarbons of natural or pyrogenous origin or mixturesthereof and which may be liquid, semisolid or solid. Examples of suchmaterials are road oils, cutbacks, asphalts, tars and pitches derivedeither from petroleum or coal. The definition also includes so-callednative asphalts. The bitumens may be derived from straight rundistillation of petroleum or from cracking processes, and may or may notbe blown or oxidized. The oxidized or blown asphalts may be thoseobtained by blowing asphalt by air or oxygenated gases, or by thecatalytic preparation of airblown asphalts using catalysts, such asphosphorus pentoxide, red phosphorus or phosphorus sulfide as describedin U. S. 2,450,756, or halide salt catalysts as described in U. S.2,421,421.

While the present invention has been described by reference to specificembodiments thereof, these are given by way of illustration only and theinvention is not to be limited thereto but includes within its scopesuch modifications and variations as come within the spirit of theappended claims.

I claim:

1. A new composition of matter comprising a major proportion ofbituminous material and from about 0.1% to about 30% of ebony fat whichebony fat is the propane-insoluble residue obtained in the solventextraction of a crude fatty material selected from the class consistingof crude animal fats, fatty oils, and fatty acids, and crude vegetablefats, fatty oils, and fatty acids, and mixtures thereof, with liquefiedpropane, said insoluble residue being insoluble in 6 to 30 volumes ofpropane at temperatures of from about F. and constituting from about0.2% to about 10% of the crude fatty material from which said insolubleresidue is extracted.

2. A new composition of matter as described in claim 1 in which thecrude fatty material is a crude animal fat.

3. A new composition of matter as described in claim 1 in which thecrude fatty material is a crude vegetable oil.

4. A roadway construction material resistant to water strippingcomprising a mineral aggregate admixed with a bituminous material andfrom about 0.1% to about 30% by weight, based on said bituminousmaterial, of ebony fat which ebony fat" is the propane-insoluble residueobtained in the solvent extraction of a crude fatty material selectedfrom the class consisting of crude animal fats, fatty oils, and fattyacids, and crude vegetable fats, fatty oils, and fatty acids, andmixtures thereof, with liquefied propane, said insoluble residue beinginsoluble in 6 to 30 volumes of propane at temperatures of from about140 F. to about 190 F. and constituting from about 0.2% to about ofthe-crude fatty material from which said insoluble residue is extracted.

5. A roadway construction material as described in claim 4 in which thecrude fatty material is crude animal fats.

'6. A roadway construction material described in claim 4 in which thecrude fatty material is crude vegetable oils.

7. A roadway construction composition described in claim in which thebituminous material is a petroleum residuum.

8. A method of forming a water-resistant bond between mineral aggregatesand a bituminous material comprising mixing said bituminous materialwith from about 0.1% to about 30% of ebony fat which ebony fat is thepropaneinsoluble residue obtained in the solvent extraction of a crudefatty material selected from the class consisting of crude animal fats,fatty oils, and fatty acids, and crude vegetable fats, fatty oils, andfatty acids, and mixtures thereof, with liquefied propane, saidinsoluble residue being insoluble in 6 to 30 volumes of propane attemperatures of from about 140 F. to about 190 F. and constituting from0.2% to about 10% of the crude fatty material from which said insolubleresi- 8 due is extracted, and applying said mixture to said mineralaggregate.

9. In the construction of a bituminous pavement in which the bituminouscoating material is applied to mineral aggregate, the improvementcomprising mixing said mineral aggregate with said bituminous materialand. incorporating in said mixture from about 0.1% to about 30% byweight, based on said bituminous material, of ebony fat which ebony fatis the propaneinsoluble residue obtained in the solvent extraction of acrude fatty material selected from the class consisting of crude animalfats, fatty oils, and fatty acids, and crude vegetable fats, fatty oils,and fatty acids, and mixtures thereof, with liquefied propane, saidinsoluble residue being insoluble in 6 to 30 volumes of propane'attemperatures of from about F. to about F. and constituting from about0.2% to about 10% of the crude fatty material from which said insolubleresidue is extracted.

FREDERICK H. MACLAREN.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 835,113 Penny Nov. 6, 1906 1,905,376 Fischer Apr. 25, 19332,329,889 Ewing Sept. 21, 1943 2,383,097 Weetman Aug. 21, 1945 FOREIGNPATENTS Number Country Date 151,666 Great Britain Oct. '7, 1920

1. A NEW COMPOSITION OF MATTER COMPRISING A MAJOR PROPORTION OFBITUMINOUS MATERIAL AND FROM ABOUT 0.1% TO ABOUT 30% OF "EBONY FAT"WHICH "EBONY FAT" IS THE PROPANE-INSOLUBLE RESIDUE OBTAINED IN THESOLVENT EXTRACTION OF A CRUDE FATTY MATERIAL SELECTED FROM THE CLASSCONSISTING OF CRUDE ANIMAL FATS, FATTY OILS, AND FATTY ACIDS, AND CRUDEVEGETABLE FATS, FATTY OILS, AND FATTY ACIDS, AND MIXTURES THEREOF, WITHLIQUEFIED PROPANE, SAID INSOLUBLE RESIDUE BEING INSOLUBLE IN 6 TO 30VOLUMES OF PROPANE AT TEMPERATURES OF FROM ABOUT 140* F. ANDCONSTITUTING FROM ABOUT 0.2% TO ABOUT 10% OF THE CRUDE FATTY MATERIALFROM WHICH SAID INSOLUBLE RESIDUE IS EXTRACTED.